


Possession

by SharkGirl



Series: SouRin Week Feb 2016 [6]
Category: Free!, X-Men - All Media Types
Genre: Clone!Sousuke, Crossover, Day 6, Day 6: Fantasy/Sci-Fi, M/M, Minor Violence, Mutant Powers, Mutants, Possession, Sci-Fi, SouRin Week, Sports Anime Crossover, Telepath!Rin, X-Men AU - Freeform
Language: English
Status: Completed
Published: 2016-02-07
Updated: 2016-02-07
Packaged: 2018-05-18 17:35:53
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,614
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5937022
Author URL: https://archiveofourown.org/users/SharkGirl/pseuds/SharkGirl
Summary: <blockquote class="userstuff">
              <p>Strange things are happening at the Aida Institute.  Well, stranger than usual.  Like the students' personal items ending up on the opposite side of the school and the doors to restricted areas opening on their own.  The teachers have started patrolling the halls in hopes of catching the culprit.  No one knows who it is.</p><p>But Sousuke's roommate has been sneaking out in the middle of the night...</p><p>Written for Day 6 of SouRin Week, Paper: Fantasy/Sci-Fi</p>
            </blockquote>





	Possession

**Author's Note:**

  * For [indevan](https://archiveofourown.org/users/indevan/gifts).



> Hello! Is it Day 6 already? (Well, not quite, but I have a relay in the morning, so I'm posting this now, hehe)
> 
> I actually wrote this submission first. It's based on the X-Men AU created by indevan/@vertigoats (If you haven't read any of their drabbles from it, you're missing out!!) It is an AU and a crossover of all of the (currently popular) sports anime. This fic only contains characters from Free! and Kuroko no Basuke, though.
> 
> If you're worried about not knowing who the KnB characters are...don't be! They're barely in it. But, here's some info:
> 
> Akashi Seijuurou - Headmaster of The Aida Institute (Charles Xavier's role from X-Men) A powerful telepath and telekinetic.  
> Furihata Kouki - Akashi's lover and a teacher at the school. He is also a mutant.  
> Momoi Satsuki - Also a teacher at the institute. She deals with the students who are too young to fight.
> 
> There is one character from X-Men:
> 
> Shadow King: Amazingly powerful telepath. His true nature is an astral form, preying on the bodies of powerful psi-sentitives and utilizing their abilities to enslave others
> 
> This story is about Rin and Sousuke, so all of their info is in the fic.
> 
> Last note, I swear. The boys are sixteen in this, so they're technically underage. I didn't tag this as underage because there are no explicit sexual scenes. Just an FYI.

It started with things being misplaced.  Small personal items like cellphones or watches disappearing during the night and reappearing on opposite ends of the school.  Next it was the food from the kitchen.  Three people’s portions of lunch, prepped the night before, would wind up missing, barely a crumb left behind.

And while pranks of this nature weren’t uncommon in a school filled with mutants – several of whom had powers that rendered them completely capable of such actions – the teachers became concerned when the doors to restricted areas were being forced open.

The first was Momoi’s office.  Then it was The Danger Room.  Next was the medical ward.

The teachers were on edge.  No matter what they did, they couldn’t catch the culprit. 

But Sousuke had an idea of who it might be.  No, he knew who it was.

Rin had started getting out of bed in the middle of the night right around the time all of this began.  At first, Sousuke thought he was going to the bathroom or maybe taking a late night walk around the halls.  Although Rin was usually in complete control of his powers, sometimes at night, when he was tired, he said he could hear everyone’s thoughts.  Almost see their dreams.

In a school full of students, that had to be quite overwhelming.

So, Sousuke ignored it at first, letting his roommate go out to clear his head as best he could.  But, once the teachers announced they’d be patrolling the halls at night in shifts, the brunet decided that maybe he should dissuade Rin from leaving.

And so, the next night, just as Sousuke was drifting off, he heard the telltale creaking of Rin’s bed and decided to act.  He opened one cerulean eye, instantly zeroing in on his roommate.  The redhead had gotten out of bed and was walking toward the door.

“Rin.”

The other teen stopped, glancing back over his shoulder at Sousuke.  It was hard to tell in the dark, but something in the other’s eyes was off.

“You shouldn’t go out tonight,” Sousuke continued.  “They’ve got eyes everywhere.”

“I hadn’t planned on sneaking away too far,” Rin replied, voice silky and smooth.  He didn’t sound like himself.

“Where were you going?” Sousuke took the bait, sitting up in bed.

They’d only been roommates for a short while.  The redhead had been assigned to Sousuke to help him acclimate to the school.  To make Sousuke feel more…human.  Sixteen years being treated as a weapon didn’t exactly make him the most personable.  But he’d really taken to Rin.  When the redhead looked at him, it was like he was more than just a tool to be used.  He felt like the other truly cared about him.

Sousuke hadn’t felt that way about anyone since his mother – no, the doctor who created him, impregnating herself instead of allowing Sousuke to grow in a tube like the other clones.  That was probably the reason why he was their only success.  HJ-037, named Sousuke by Dr. Yamazaki.  He lived with her for twelve years before they made him kill her and he lost the only warmth he’d ever felt.

Until he met Rin.

“Where were you going?” Sousuke asked again.

“Out,” Rin smiled at him, teeth unbelievably sharp.  Sousuke had seen the redhead smile dozens of times since he came to the Aida Institute.  He would have noticed if the other teen had a mouthful of pointed teeth.  He’d heard of mutants having secondary mutations, but something was still strange about their sudden appearance.

“Rin.”

“What is it, Sousuke?” The way Rin said his name, like he was tasting it, sent a shiver up the brunet’s spine.  It was an unusual feeling, but not unpleasant.  Still…

“I asked you where you were going.”

“Well,” Rin walked over to him, swaying his hips.  “I had planned on going out and sating this hunger…” he placed a hand on his stomach, splaying his fingers.

“Food?” Sousuke asked.  “So it _was_ you stealing from the kitchen.”

“Yes, that was me,” the redhead chuckled.  “But that’s not the kind of hunger I’m talking about…” he let his hand slip lower to toy with the hem of his nightshirt, capturing his lower lip between sharp teeth.

Sousuke stared at him blankly, unsure of what he meant.  Although he’d been merely a human weapon up until this point, he understood the body’s needs.  If you’re thirsty, drink.  If you’re hungry, eat.  So, what did Rin mean?

“Ah, that’s right,” Rin walked forward, nudging Sousuke’s knees apart and standing between his legs.  He was so close now that Sousuke had to look up to meet his gaze.  “They never taught you about that, did they?”  He reached a hand out and caressed the side of Sousuke’s face.  It felt nice.  Sousuke would have leaned into the touch, but something in the crimson eyes staring down at him made him hesitate.

“Teach me about what?”

“Sex,” he said simply, smirking at the end.

Sousuke went over what he knew about the word.  Sexual reproduction: the creation of new living organisms by combining genetic information from two individuals of different types.  That’s all he’d been taught, a mere definition, skimmed over in his studies.

Rin, seemingly sensing Sousuke's confusion, continued.

“Carnal pleasures,” he explained.  “There are things I’ve been longing to feel,” he moved his hand lower and hooked his thumb under the waistband of his pajama pants.  “So, I’m going to go out and fulfill this desire,” Rin made to walk away, but Sousuke wrapped a hand around the other teen’s wrist.

“What are you talking about?” his narrowed his eyes, demanding an explanation and wanting to know why Rin was acting so strangely.

“Haven’t you felt it, Sousuke?” Rin turned back to face him.  “The ache."  His free hand returned to his stomach, sliding down until he reached the crotch of his pants, hissing as he gave his front a squeeze.

Sousuke averted his eyes, feeling as though he was seeing something he shouldn’t be.

“You’ve felt it, too, right, Sousuke?” Rin kept saying his name, letting it drip like honey off of his tongue.  “I’ve heard you at night…”

“You…” cerulean eyes snapped back to Rin’s.

Sometimes Sousuke would lay awake at night, unable to sleep because his mind was plagued with visions of the death and destruction he’d caused.

“I’m not talking about your past,” Rin said.

Sousuke blinked in surprise before he remembered that the redhead could read his mind.  Of course, Rin had said time and again that he never did so without permission, unless of course, he was fighting an enemy.

“Rin-”

“I’m talking about the dreams you have…” he breathed, leaning closer.  “Your innocent mind can’t produce imagery, but the want is there,” he explained.  “Such want you have, Sousuke…” he lowered his head, his warm breath stirring the hair just above the brunet’s ear, sending a tingle up his neck.  “Do you want me to show you?”

“Show me…?” Sousuke looked up him and suddenly, he was on his back on the bed, his legs still dangling off of the side.

“I usually prefer women, but there’s a hunger inside, too,” he purred, pressing Sousuke’s body into the mattress and licking his neck.

“Rin…what are you-?”

“Wow, such a reaction,” Rin gasped, pulling back and staring down.  “This body must really want you,” he palmed himself again and looked at Sousuke with heated eyes, pupils blown.

But something was wrong.  Rin wasn’t acting at all like himself.  He wasn’t a perfect student, but he wasn’t someone who’d just sneak out at all hours.  And he certainly wasn’t…whatever he was being right now.

“Don’t think so much, Sousuke,” Rin leaned down again, rolling his hips against the brunet’s.  “A-Ah, you see?” he purred.  “You want it, t-”

“Who are you?” Sousuke glared up at him.  Crimson eyes widened for a moment before looking bored.  “Who are you?” he repeated.

“I’m Matsuoka Rin. Your roommate and-”

“No,” Sousuke pushed him away and sat up.  “You’re not Rin.”

“How perceptive,” Rin, or the thing that looked like him, narrowed his eyes.  “It seems I underestimated your relationship with this boy.”

“Where’s Rin?” Sousuke stood up, hands balled into fists at his sides.

How long had Rin been gone?  Is the reason Rin had been acting so distant lately because he wasn’t Rin at all?

“Rin hasn’t been anywhere,” the redhead answered, reading his mind again.  “I am Rin.”

“No, you’re not.”

“You’re really worried about him, aren’t you?” he flashed sharp teeth.  “And I thought you weapons couldn’t feel-” he was cut off when Sousuke lunged at him, a hand pressing against the fake Rin’s windpipe and his knee pushing him up against the wall.

“ _Where_ is Rin?” Sousuke roared.

“I, hrgh, told you,” he wheezed.  “I _am_ Rin.”

“But-”

“And, unless you’d like to asphyxiate your little boyfriend,” crimson eyes narrowed at him, “I suggest you release his body.”  Sousuke snatched his hand away as though he’d been burned.  “There,” the fake Rin rubbed at his throat.  “Now, if you play nice, you can have one night with your precious Rin,” he bit his lip and pulled up the hem of his shirt.  “But,” his voice became dark, “whether you fuck him or not, you will not live to see tomorrow.”

“What are you talking about?” Sousuke glowered.

“I have much bigger plans than simply taking over this low-level telepath,” he explained.  “I have another goal in mind,” he smirked.  “But, your body seems to get a reaction from him, so I don’t mind doing it once…”

“Get out,” Sousuke growled.

“Excuse me?”

“Get out of his body,” he threatened.

“Pity,” the fake Rin lowered his eyelids and took a deep breath.  “I was hoping to have a little fun with you before I killed you.”  He sighed.  “Oh well,” his eyes shot open and he grinned, sharp teeth glinting in the moonlight shining through the window.  “Sorry, HJ-037.”  Then he lunged at him, knocking Sousuke to the ground.

Sousuke grunted as his back came in contact with the hard wooden floor.  He gripped at the hands wrapped around his neck, the other’s thumbs pressing down on his windpipe.  He should have easily been able to throw Rin’s smaller form off of him, but the imposter had taken him by surprise and his arms and legs were starting to feel heavier and heavier as the last of the air was squeezed out of his lungs.

“So, this is the only successful clone of the great Hyuuga Junpei,” the other man snorted.  “How easily you’re taken down.”

Sousuke looked up at him, his vision beginning to swim.  He removed one of his hands from the redhead’s wrists and brought it up to Rin’s face, brushing the backs of his fingers against his cheek.

“R…R-i…n...”

Suddenly, the thumbs pressing down eased up a bit.

“What?” the redhead hissed.  “What’s wrong with this body?!” he screamed, the fingers around Sousuke’s neck loosening.  “Kill him!”

Sousuke took his opportunity to throw Rin off of him.  He rolled away, as far as he could get in their cramped two-person room and leaned against his bed as he coughed, taking in some much needed air.

“Damn it!” the other man roared, standing back up and glaring at him.  “This time I’ll make it quick.”

Sousuke didn’t know what to do.  He didn’t want to hurt Rin’s body.  But he had to stop whatever this was from killing him.  Maybe he could scare him off.

He focused on his powers, feeling his hands heat up with blue flames.  He held the glowing balls of fire toward the other teen, hoping the sight would distract the other long enough for Sousuke to make a break for the door.

“You think I’m scared of your little pyrotechnics?” the fake Rin threw his head back and barked out a laugh.  “You won’t hurt me,” he said.  “Not while I’m in Rin’s body.”

Sousuke needed to think of something and fast.  He glanced over at the door just behind the other teen.

“You’ll never make it in time,” the redhead gave a wicked grin.  “Furihata-sensei is on the other side of campus and Momoi-sensei is near the kitchen,” he laughed.  “By the time you make it to them,” he paused, “ ** _if_** you make it to them,” he said, “I’ll be gone.”

“I won’t let you run off with Rin’s body,” Sousuke glared, but extinguished his flames.

“Giving up already?” he cocked his head to the side.  But Sousuke didn’t get a chance to answer.  The door to their room flew open.  Both teens turned to see Akashi standing in the doorway.  “How?” the fake Rin took a step back.  “I didn’t sense any beta brainwaves this close!”

“Whoever you are,” Akashi stepped forward.  “You’re a fool to think I can’t mask mine.”

“Akashi-sensei, you know he’s not Rin?” Sousuke asked.

“I thought he’d been acting off in our simulations,” the professor said.  “But when I felt Rin fighting not too long ago, I knew something was wrong.”

“Felt him…fighting?” Sousuke furrowed his brow.  Wasn’t the imposter the one doing the fighting?

“He wouldn’t kill Sousuke, would he?” Akashi turned his attention onto the younger redhead, recognition flashing in his eyes.  The other simply glared back at him.  “You’ve lost your touch, Shadow King,” Akashi smirked.  “Can’t even control a teenager?”

“Shut up!” he growled.  “I underestimated him, I’ll admit,” he practically hissed.  “But, no matter,” he shrugged.  “I was growing tired of this body, anyway.”  His crimson eyes flashed.  He took a step closer to Akashi and then frowned.  “Four against one,” he spat.  “That’s not very fair, is it?”

“Four?” Sousuke looked around.

“And more will come if I bid them to,” Akashi stood his ground.

“Then we’ll have to finish this later,” the fake Rin took a step back and relaxed his arms at his sides.  “Too bad, Sousuke,” he turned to look at him.  “I was so looking forward to seeing the face you’d make when Rin killed you.”

And before Sousuke could reply, Rin jumped backwards, throwing himself through the window, shattering the glass and sending shards flying in every direction.

“Rin!” Sousuke called and ran after him, leaning against the windowsill and ignoring the broken glass that bit into his skin.  He peered down, cerulean eyes searching for his roommate.  His friend.  But the redhead was nowhere in sight.

“He won’t kill him,” Akashi said from behind him.  “He needs Rin’s body until he can find another host.”

“Another…host?” Sousuke drew his brows together and shook his head.  “What’s going on, Akashi-sensei?”

“Akashi-kun!” Momoi appeared in the doorway.  “I came as soon as I-” but she stopped when she noticed the broken glass.  “What happened?”

“Sei!” Furihata was right behind her.  “Are the boys…” he trailed off when he saw Sousuke’s bloodied hands.  “What happened here?”

“He’s back,” Akashi turned to face them.  “The Shadow King.”

Sousuke didn’t know who the Shadow King was or what he wanted to do.  All he knew was Rin was missing and in danger.  He opened his mouth, but Akashi interrupted him.

“I’ll explain on the way to the medical ward,” he said, eyes boring into Sousuke’s.  “We must act quickly if we’re to save Rin’s life.”

Sousuke hardened his gaze, ignoring the pain he felt in his chest at the thought of Rin possibly losing his life.

“Right,” he nodded and followed the teachers out of their room.  Whatever they needed him to do, he’d do it.  He glanced back at the broken window and then continued walking down the hallway.

**Author's Note:**

> I really love indevan's X-Men AU and I just HAD to write this scene. I've been wanting to write it since they told me about Sousuke's past.
> 
> Let me know what you think and hit me up on tumblr~  
> http://jubesy.tumblr.com/  
> Or check out our official Sports Anime Xmen AU tumblr [@saxmenau](http://saxmenau.tumblr.com)!!


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